Recombinant Mouse Endocan Protein, CF

Endocan (endothelial cell proteoglycan; also known as endothelial‑cell specific molecule‑1 [ESM‑1]), is a 50 kDa, monomeric, secreted, cysteine‑rich proteoglycan identified initially in endothelial cells of the kidney and lung (1). Mouse Endocan is synthesized as a 184 amino acid (aa) precursor that contains a 21 aa signal sequence and a 20 kDa, 163 aa mature region (2). The N‑terminal 2/3 of the molecule contains 18 cysteine residues and there are no potential N‑linked glycosylation sites. Based on human Endocan, there are at least two potential O‑linked glycosylation sites, one of which will likely be utilized on Ser at position # 136 of the mature molecule (3). The posttranslational modification is approximately 30 kDa in size. It consists of a single dermatan sulfate chain that contains 4‑O sulfated N‑acetyl galactosamine with alpha‑iduronate. This chain is suggested to bind HGF and contribute to HGF mitogenic activity (4). Mature mouse Endocan is 96% and 74% aa identical to rat and human Endocan, respectively. In human, there is a potential for an alternate splice variant. It shows a deletion of aa’s 82 through 131, a range which would not remove the dermatan sulfate attachment site (4). It is not known if such a splice form exists in mouse. Endocan is expressed by endothelial cells, adipocytes, bronchial epithelium and distal renal tubular epithelium (1, 5, 6). It is upregulated by TNF‑ alpha and VEGF, (1, 7) and is known to bind to LFA‑1 ( alpha_L beta₂) on the surface of PBMCs, blocking LFA‑1 interaction with ICAM‑1 (8). Normal circulating levels of Endocan are approximately 1 ng/mL (6).